Field
The disclosure relates generally to electronic circuits, in particular, to apparatus and methods for monitoring and/or prevention of failures (or potential failures) relating to electromigration.
Background
Thermal management and management of average current densities in conductors are increasingly of concern in the operation of integrated circuits (ICs). For example, these issues may affect interconnects used in ICs in the mobile, server and automotive industries. Both of these issues may significantly affect the lifetime of interconnects in the back end of line (BEOL).
Interconnects may be especially vulnerable to electromigration (EM) failures. EM is a phenomenon relating to the self-diffusion of metallic ions (e.g., ions in a conductor) that results from electric field and movement of conducting electrons. EM may be strongly impacted by temperature and average direct current density, especially as current densities increase and the structural size of electronics (e.g., the width of conductors in ICs) decrease.
Electromigration damage may be cumulative in that the migration of ions may contribute over time to cause an open circuit (due to voids forming from ion migration) or a short circuit (due to hillocks formed by ion accumulation). A failure of even a single conductor may cause an IC to malfunction. If the malfunction occurs before an end of a stipulated lifetime of the IC, expensive recalls or loss of market share may result.